Service forfeiture

My car service was due in April and it was during lockdown and i assumed that since it has not reached 60000 km i can take it anytime and when i did i was told it has lapsed and i have forfeited my benefits. They said it was not their fault and I assume it was mine. They didn’t provide any form of communication whatsoever related to that. I ended paying cash. For them to take advantage of this times to make profit is really disturbing and disappointing